1. Field of the Disclosure
The disclosure relates generally to sensing user input provided by touch on a display screen.
2. The Prior Art
Background
Capacitive touch screens are know in the art. Various methods have been developed for sensing the position touched on a display screen. Such methods include specifically generating a signal that are altered by the capacitance of the user's finger to determine the position on a screen. Other methods include the use of surface acoustic wave (SAW) devices, resistive devices, and the like.
One drawback of prior art devices is that generally such devices are self-contained units embodied in glass sensor panels that are separately attached over the display. Such units tend to be complicated and expensive as they contain the circuitry necessary for generating and sensing the separate signals used to perform the position location. Additionally, the devices of the prior art may impart undesired optical effects on the video display output which much pass through the glass sensor panel. Finally, the devices of the prior art must be carefully aligned to calibrate the position location performed by the device with the video output provided by the display. Thus different sized displays require a correspondingly sized sensor panel.